Laser welding method and apparatus

Abstract

The application provides a laser welding method and device, the laser welding method comprises the following steps: controlling a laser beam to irradiate a preset welding point on a stack, so as to generate a keyhole and a molten pool surrounding the keyhole at the preset welding point; controlling a target moving object to move along a first welding path; after the target moving object moves along the first welding path, controlling the target moving object to start from a first point on a reference circle, travel along the reference circle and swing alternately in a first direction and a second direction in the radial direction of the reference circle; when the target moving object reaches a second point on the reference circle, recording the moving track of the target moving object between the first point and the second point as a second welding path. The application improves the metal fusion, and improves the welding strength and welding stability.

Description

Technical Field

[0001] This invention belongs to the field of laser welding technology, and in particular relates to a laser welding method and apparatus. Background Technology

[0002] Currently, during remote laser welding of coated metal workpieces (such as steel workpieces with silicon or aluminum alloy anti-high-temperature oxidation coatings), the coating can melt and enter the molten pool. For example, when the aluminum alloy coating on a steel workpiece melts, aluminum enters the molten pool, causing segregation of the metal composition. This results in a higher ferrite content in areas rich in aluminum compared to areas with lower aluminum content. Since aluminum is present in the surface coating, the ferrite is also mainly distributed along the fusion line (the fusion line between the two welded metal workpieces) near the weld edge or surface. Because ferrite is a high-temperature formed structure, and its strength after cooling is lower than that of the martensite main structure of the weld, the weld edge or surface where ferrite is mainly distributed is more likely to become crack initiation sites or crack propagation paths under tensile or other external forces. This leads to a reduction in the strength of the welded joint. Summary of the Invention

[0003] This invention addresses the technical problem in the prior art where the high-temperature oxidation-resistant coating melts and enters the molten pool, reducing the strength of the welded joint, by providing a laser welding method and apparatus.

[0004] In view of the above technical problems, embodiments of the present invention provide a laser welding method, including:

[0005] A laser beam is controlled to irradiate a preset welding point on a stacked component to generate a keyhole and a molten pool surrounding the keyhole at the preset welding point; the stacked component includes at least two metal workpieces stacked on top of each other; at least one of the metal workpieces is provided with a high-temperature oxidation resistant coating;

[0006] The target moving object is controlled to move along a first welding path; the first welding path is a spiral line rotating around the preset welding point; the target moving object is at least one of the laser beam and the stacked components;

[0007] After the target moving object has completed moving along the first welding path, the target moving object is controlled to start from a first point on the reference circle, move along the reference circle, and alternately swing in the radial direction of the reference circle in a first direction and a second direction; the first direction is towards the center of the reference circle; the second direction is towards the direction away from the center of the reference circle; the center of the reference circle is the preset welding point;

[0008] When the target moving object arrives at the second point on the reference circle, the movement trajectory of the target moving object between the first point and the second point is recorded as the second welding path; the second welding path at least partially overlaps with the first welding path.

[0009] A laser welding apparatus includes a laser and a controller, the laser being used to emit a laser beam and the controller being used to control the laser to perform the laser welding method.

[0010] In the laser welding method and apparatus of the present invention, the laser welding method includes controlling a laser beam to irradiate a preset welding point on a stacked component to generate a keyhole and a molten pool surrounding the keyhole at the preset welding point; the stacked component includes at least two stacked metal workpieces; at least one of the metal workpieces is provided with a high-temperature oxidation resistant coating; controlling a target moving object to move along a first welding path; the first welding path is a spiral rotating around the preset welding point; the target moving object is at least one of the laser beam and the stacked component; after the target moving object has moved along the first welding path, controlling the target moving object to move along the reference circle starting from a first point on the reference circle and alternately swinging in a first direction and a second direction in the radial direction of the reference circle; the first direction is towards the center of the reference circle; the second direction is towards the direction away from the center of the reference circle; the center of the reference circle is the preset welding point; the radius of the reference circle is less than or equal to the maximum distance between the first welding path and the preset welding point; when the target moving object reaches a second point on the reference circle, the movement trajectory of the target moving object between the first point and the second point is recorded as a second welding path; the second welding path at least partially overlaps with the first welding path.

[0011] After generating a keyhole and a molten pool around the keyhole at a preset welding point through laser irradiation, the present invention expands the molten pool by controlling a target moving object to move along a first welding path, thereby allowing the ferrite generated based on the high-temperature oxidation-resistant coating to be better dispersed along the fusion line. Subsequently, by controlling the target moving object to move along a second welding path, the outer ring of the first welding path is stirred, further agitating and dispersing the ferrite structure in the molten pool, reducing segregation in the molten pool, avoiding ferrite enrichment in a certain area, improving metal fusion, and enhancing welding strength and welding stability. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0013] Figure 1 This is a schematic flowchart of a laser welding method provided in an embodiment of the present invention.

[0014] Figure 2 This is a schematic diagram of the first welding path and reference circle of a laser welding method provided in an embodiment of the present invention.

[0015] Figure 3 This is a schematic diagram of the second welding path of a laser welding method provided in an embodiment of the present invention.

[0016] Figure 4 This is a schematic diagram of the second welding path of a laser welding method provided in another embodiment of the present invention.

[0017] Figure 5 This is a schematic flowchart of a laser welding method provided in another embodiment of the present invention.

[0018] Figure 6 This is a schematic diagram of the first welding path and the second welding path of the laser welding method provided in an embodiment of the present invention.

[0019] Figure 7 This is a schematic diagram of the first welding path and the second welding path of the laser welding method provided in another embodiment of the present invention.

[0020] The reference numerals in the accompanying drawings are as follows:

[0021] 100. Preset welding point; 200. First welding path; 210. Target starting point; 220. Target ending point; 300. Reference circle; 310. First point; 320. First direction; 330. Second direction; 340. Target travel direction; 400. Second welding path; 410. First arc; 420. Second arc; 510. First X direction; 520. First Y direction; 610. Second X direction; 620. Second Y direction; 710. First boundary circle; 720. Second boundary circle. Detailed Implementation

[0022] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0023] It should be understood that the terms "upper", "lower", "left", "right", "front", "rear", "middle", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of the present invention.

[0024] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a laser welding method, including steps S10 to S40:

[0025] S10, control the laser beam to irradiate a preset welding point 100 on the stacked parts to generate a keyhole and a molten pool around the keyhole at the preset welding point 100; the stacked parts include at least two metal workpieces stacked on top of each other; at least one of the metal workpieces is provided with a high-temperature oxidation resistant coating.

[0026] Understandably, when at least two metal workpieces include overlapping first and second metal workpieces, the first metal workpiece has a first top surface and a first mating surface, and the second metal workpiece has a second mating surface and a first bottom surface. The first and second mating surfaces constitute a first bonding interface. Furthermore, the bonding interfaces (the first bonding interface and the second bonding interface mentioned later) may have a gap or be completely zero-gap. Further, the stacked component may also include a third metal workpiece, which has a third mating surface and a second bottom surface, and the first bottom surface and the third mating surface constitute a second bonding interface. The metal workpiece substrate may be steel or aluminum. In the above embodiments, at least one of the bonding interfaces, the surface of which has a high-temperature oxidation resistant coating, such as a silicon alloy, aluminum alloy, or aluminum-silicon alloy, can be achieved by methods such as electrochemical deposition or thermal deposition.

[0027] Understandably, the preset welding points 100 can be set at any welding location on the bonding interface (the first bonding interface and the second bonding interface mentioned later) as needed, and the number and arrangement of the preset welding points 100 can be set according to requirements. The keyhole and the molten pool need to penetrate the bonding surface between at least two stacked metal workpieces, and can partially or completely penetrate the stacked parts. By controlling the physical parameters of the laser beam (e.g., power or spot size), the power density of the laser beam can be changed, thereby allowing the keyhole and the molten pool to partially or completely penetrate the stacked parts.

[0028] S20, control the target moving object to move along the first welding path 200; the first welding path 200 is a spiral line rotating around the preset welding point 100; the target moving object is at least one of the laser beam and the stacked parts.

[0029] Understandably, there is relative motion between the laser beam and the stacked components. That is, the laser beam can be controlled to move, thereby generating relative motion between the laser beam and the stacked components; the stacked components can also be controlled to move, thereby generating relative motion between the laser beam and the stacked components; or both the laser beam and the stacked components can be controlled to move simultaneously, thereby generating relative motion between them. The first welding path 200 has a target start point 210 and a target end point 220. The target start point 210 is the endpoint on the spiral line near the preset welding point 100, and the target end point 220 is the endpoint on the spiral line away from the preset welding point 100. The laser beam can move along the first welding path 200 at a fixed speed, thereby uniformly heating and stirring the stacked components. The first welding path 200 can be set to rotate clockwise or counterclockwise around the preset welding point 100 as needed.

[0030] S30, after the target moving object has completed moving along the first welding path 200, the target moving object is controlled to move along the reference circle 300, starting from a first point 310 on the reference circle 300, and alternately swinging in the radial direction of the reference circle 300 in a first direction 320 and a second direction 330; the first direction 320 is towards the center of the reference circle 300; the second direction 330 is towards the direction away from the center of the reference circle 300; the center of the reference circle 300 is the preset welding point 100. Preferably, the radius of the reference circle 300 is less than or equal to the maximum distance between the first welding path 200 and the preset welding point 100, therefore, the reference circle 300 must have at least one intersection with the first welding path 200.

[0031] Understandably, the first point 310 can be set on the reference circle 300 according to actual conditions. Furthermore, the first point 310 can be set on the reference circle 300 at the point closest to the end of the first welding path 200, thereby reducing the time required to control the target moving object to move from the end of the first welding path 200 to the first point 310, thus improving efficiency.

[0032] In this embodiment, after the target moving object has moved along the first welding path 200, the target moving object takes the first point 310 on the reference circle 300 as the starting point and moves along the reference circle 300 in the target travel direction 340 (counterclockwise or clockwise). During the above-mentioned travel, the target moving object is simultaneously controlled to swing alternately in the first direction 320 and the second direction 330 radially along the reference circle 300. It can be understood that the target travel direction 340 can be the same as or opposite to the rotation direction of the spiral.

[0033] In one embodiment, the swing trajectory formed between any two swing direction changes (for example, the swing trajectory formed between the first time point when the first direction 320 changes to the second direction 330 and the second time point when the second direction 330 changes to the first direction 320, or the swing trajectory formed between the third time point when the second direction 330 changes to the first direction 320 and the fourth time point when the first direction 320 changes to the second direction 330) intersects with the reference circle 300.

[0034] like Figure 3 As shown, one alternating oscillation includes one consecutive oscillation along a first direction 320 and one along a second direction 330, and the order of the oscillations along the first direction 320 and the second direction 330 in one alternating oscillation is not limited; however, in two consecutive adjacent alternating oscillations, the order of the oscillations along the first direction 320 and the second direction 330 must be consistent. Understandably, the oscillation trajectory formed by each alternating oscillation intersects with the reference circle 300. In this invention, the oscillation trajectory formed by each alternating oscillation can be the same or different. Furthermore, having the same oscillation trajectory for each alternating oscillation allows for more uniform stirring of the stacked components.

[0035] S40, when the target moving object arrives at the second point on the reference circle 300, the movement trajectory of the target moving object between the first point 310 and the second point is recorded as a second welding path 400; the second welding path 400 at least partially overlaps with the first welding path 200. It can be understood that the second point may or may not coincide with the first point 310. When the second point coincides with the first point 310, the second welding path 400 is a circular path that at least partially overlaps with the first welding path 200. The at least partial overlap of the second welding path 400 with the first welding path 200 allows the target moving object to further agitate the outer portion of the first welding path 200 by passing through the second welding path 400.

[0036] Understandably, the laser beam can be a single laser beam or a combined laser beam. When the laser beam is a combined laser beam, it includes a central laser beam and a ring laser beam. The ring laser beam surrounds the central laser beam and is concentric with it, forming a novel heat source composed of a central Gaussian heat source beam and a ring beam. Both the central laser beam and the ring laser beam can be independently adjusted in power. Under the same laser power and external conditions, the power density of the central laser beam is higher than that of the ring laser beam. The high-power-density central laser beam is mainly used to irradiate the preset welding point 100 on the stacked parts in step S10, thereby generating a keyhole and a molten pool. The low-power-density ring laser beam is mainly used to stabilize the keyhole in step S10, preventing metal cooling and solidification, and to move along the first welding path 200 and the second welding path 400 in steps S20, S30, and S40, thereby stabilizing the keyhole and stirring and expanding the molten pool. Furthermore, in step S20, the power of the central laser beam can be set to at least twice the power of the ring laser beam, thereby obtaining excellent solder joints. In steps S30 and S40, the power of the central laser beam can be set to be less than the power of the ring laser beam, thereby preventing the solder joint from overheating, and through the oscillation of the ring laser beam, solder joints with less collapse, stronger molten pool flow, and more uniform stirring can be obtained. In another embodiment, when the laser beam is a single laser beam, different powers can be set for the single laser beam, so that the preset solder joint 100 irradiated on the stacked parts in step S10 can also be obtained by moving along the first welding path 200 and the second welding path 400 in steps S20, S30, and S40, resulting in solder joints with less collapse, stronger molten pool flow, and more uniform stirring.

[0037] In this embodiment of the invention, after a keyhole and a molten pool surrounding the keyhole are generated by laser beam irradiation at the preset welding point 100, the upper part of the molten pool is expanded by controlling the target moving object to move along the first welding path 200. This allows the ferrite generated based on the high-temperature oxidation coating to be better reduced, refined, and dispersed along the fusion line. Then, the target moving object is controlled to move along the second welding path 400 to stir the outer ring of the first welding path 200, thereby further stirring and dispersing the ferrite structure in the molten pool. This reduces segregation in the molten pool, prevents elements that promote the formation of harmful structures from accumulating in a certain area and forming a brittle phase structure, and ultimately reduces the joint strength, thereby improving metal fusion and enhancing welding strength and welding stability.

[0038] like Figure 3As shown, in one embodiment, in the second welding path 400, the trajectory that alternates once in the first direction 320 and the second direction 330 along the radial direction of the reference circle 300 is a circular oscillation trajectory, and two adjacent circular oscillation trajectories intersect.

[0039] Understandably, the annular oscillation trajectory can be a circular annular oscillation trajectory, an elliptical annular oscillation trajectory, or an annular oscillation trajectory of other shapes (such as circles, irregular rings, etc.). In this embodiment, the annular oscillation trajectories formed by each alternating oscillation can be the same or different. Furthermore, the annular oscillation trajectories formed by each alternating oscillation are the same, which can more evenly stir the stacked parts. In addition, the intersection of two adjacent annular oscillation trajectories can fully and evenly stir the outer ring portion of the first welding path 200, thereby ensuring sufficient dispersion of ferrite in the molten pool.

[0040] In one embodiment, the first motion coordinates of the target moving object as it moves along the second welding path 400 are determined according to the following curve equation:

[0041] S1(t) = [x1(t), y1(t)]

[0042]

[0043] y1(t)=a y1 ·sin(2πf·t)

[0044] in:

[0045] t is the time point corresponding to when the target moving object moves along the second welding path 400;

[0046] S1(t) is the first motion coordinate corresponding to time point t in the first dynamic coordinate system; the first X direction 510 of the first dynamic coordinate system is the tangent direction of the reference circle 300, and the first Y direction 520 is the direction perpendicular to the first X direction 510 in the plane where the reference circle 300 is located.

[0047] x1(t) is the first X-coordinate in the first motion coordinate system corresponding to time point t;

[0048] y1(t) is the first Y-coordinate in the first motion coordinate system corresponding to time point t;

[0049] v1 is the first preset speed at which the center point of the circular swing trajectory travels along the reference circle 300; for example, when the circular swing trajectory is elliptical, the center point of the circular swing trajectory is the midpoint of the elliptical circular swing trajectory, and the center point of the irregular circular swing trajectory can be its center of gravity, etc.

[0050] a x1 The amplitude in the X direction is equal to half the width of the circular oscillation trajectory in the first X direction 510. For example, if the circular oscillation trajectory is elliptical and its minor radius direction is parallel to the tangent direction of the reference circle, then the amplitude in the X direction is equal to the minor radius of the elliptical circular oscillation trajectory.

[0051] a y1 The amplitude in the Y direction is equal to half the height of the circular oscillation trajectory in the first Y direction (520°). For example, if the circular oscillation trajectory is elliptical and its major radius is perpendicular to the tangent direction of the reference circle, then the amplitude in the Y direction is equal to the major radius of the elliptical circular oscillation trajectory.

[0052] Understandably, the first dynamic coordinate system dynamically changes along the circumference of the reference circle 300. When the tangent direction of the reference circle 300 is taken as the first X direction 510 of the first dynamic coordinate system, the direction perpendicular to the first X direction 510 will be taken as the first Y direction 520 of the first dynamic coordinate system, thereby forming a first dynamic coordinate system with X and Y coordinates and lying in the same plane as the reference circle 300. Then, the second welding path 400 is determined according to the first dynamic coordinate system. The first preset movement speed can be set according to requirements, as long as it ensures that within a complete circular swing trajectory, two adjacent circular swing trajectories have at least one intersection point.

[0053] In one embodiment, the Y-axis amplitude is less than the helical spacing of the first welding path 200, and twice the Y-axis amplitude plus the laser beam spot diameter is greater than the helical spacing. Understandably, the Y-axis amplitude is also half the length of a complete circular oscillation trajectory in the first Y direction 520. Twice the Y-axis amplitude (i.e., the length of a complete circular oscillation trajectory in the first Y direction 520) plus the laser beam spot diameter is greater than the helical spacing. This means that when the second welding path 400 oscillates alternately radially along the reference circle 300 towards the first direction 320 and the second direction 330, it ensures that the second welding path 400 intersects at least partially with the outer ring of the first welding path 200, thereby allowing sufficient agitation of the outer ring portion of the first welding path 200.

[0054] In one embodiment, the X-axis amplitude is determined based on the power of the laser beam and the first preset movement speed. Understandably, the X-axis amplitude is determined based on the power of the laser beam; when the laser beam power is high, the X-axis amplitude can be set to a larger value, and when the laser beam power is low, the X-axis amplitude can be set to a smaller value. Furthermore, the setting of the X-axis amplitude also needs to ensure that, under the first preset movement speed, two adjacent annular oscillation trajectories intersect at least once; therefore, the X-axis amplitude also needs to be determined based on the first preset movement speed.

[0055] like Figure 4 As shown, in one embodiment, in the second welding path 400, the trajectory that alternates once in the first direction 320 and the second direction 330 along the radial direction of the reference circle 300 is a transverse wave vibration trajectory with one wavelength, and the connection point between two adjacent transverse wave vibration trajectories is a wave crest or a wave trough. That is, in the above transverse wave vibration trajectory, the vibration trajectory between any two adjacent wave crests or two adjacent wave troughs is the trajectory that alternates once. It can be understood that the transverse wave vibration trajectory can be a sinusoidal transverse wave vibration trajectory, or a triangular transverse wave vibration trajectory, a square transverse wave vibration trajectory, or a circular arc transverse wave vibration trajectory, etc., as long as it alternates in the radial direction of the reference circle 300 along the first direction 320 and the second direction 330. In this embodiment, the transverse wave vibration trajectory formed by each alternating oscillation is the same, which can more evenly and thoroughly agitate the stacked parts, thereby making the ferrite in the molten pool fully dispersed.

[0056] In one embodiment, the second motion coordinates of the target moving object as it moves along the second welding path 400 are determined according to the following curve equation:

[0057] S2(t) = [x2(t), y2(t)]

[0058] x2(t)=v2t

[0059] y2(t)=a y2 ·sin(2tπf·t)

[0060] in:

[0061] t is the time point corresponding to when the target moving object moves along the second welding path 400;

[0062] S2(t) is the second motion coordinate corresponding to time point t in the second dynamic coordinate system; the second X direction 610 of the second dynamic coordinate system is the tangent direction of the reference circle 300, and the second Y direction 620 is the direction perpendicular to the second X direction in the plane where the reference circle 300 is located;

[0063] x2(t) is the second X-coordinate in the motion coordinates corresponding to time point t;

[0064] y2(t) is the second Y-coordinate in the motion coordinates corresponding to time point t;

[0065] v2 is the second preset speed at which the center point of the transverse wave vibration trajectory travels along the reference circle 300; the center point of the transverse wave vibration trajectory is the intersection of the transverse wave vibration trajectory and the X coordinate of the second dynamic coordinate system.

[0066] a y2 The transverse wave amplitude is the transverse wave amplitude of the transverse wave vibration trajectory in the second Y direction at 620°.

[0067] Understandably, the second dynamic coordinate system dynamically changes along the circumference of the reference circle 300. When the tangent direction of the reference circle 300 is taken as the second X direction 610 of the second dynamic coordinate system, the direction perpendicular to the second X direction 610 will be taken as the second Y direction 620 of the second dynamic coordinate system, thereby forming a second dynamic coordinate system with X and Y coordinates and lying in the same plane as the reference circle 300, and then the second welding path 400 is determined by the second dynamic coordinate system.

[0068] In one embodiment, the transverse wave amplitude is less than the helical spacing of the first welding path 200, and twice the transverse wave amplitude plus the laser beam spot diameter is greater than the helical spacing. Understandably, the transverse wave amplitude is also the amplitude length of a complete transverse wave vibration trajectory. Twice the transverse wave amplitude is also the distance between the crest and trough of a complete transverse wave vibration trajectory in the second Y direction 620. Setting the sum of twice the transverse wave amplitude and the laser beam spot diameter to be greater than the helical spacing ensures that when the second welding path 400 alternates between the first direction 320 and the second direction 330 radially along the reference circle 300, it intersects with the outer ring portion of the first welding path 200, thereby allowing for sufficient agitation of the outer ring portion of the first welding path 200.

[0069] like Figure 5 As shown, in one embodiment, after recording the movement trajectory of the target moving object between the first point 310 and the second point as the second welding path 400 when the target moving object arrives at the second point on the reference circle 300 in step S40, the method further includes the following step:

[0070] S50, perform a preset number of deflection welding operations. The deflection welding operation includes: controlling the target moving object to move from the first point 310 of the deflected second welding path 400 as the starting point; when the target moving object reaches the second point of the deflected second welding path 400, confirm that the current deflection welding operation is completed; wherein, the second welding path 400 rotates by a preset deflection angle around the preset welding point 100 to achieve deflection. It can be understood that the preset number of operations and the preset deflection angle can be set according to requirements. Further, if the preset number of operations is N, after performing the preset number of deflection welding operations, N+1 second welding paths 400 will be formed, and each second welding path 400 will be deflected around the preset welding point 100 as the center. Each second welding path 400 will be deflected by a preset deflection angle relative to the previously formed second welding path 400, so that the multiple second welding paths 400 can be evenly distributed.

[0071] Specifically, such as Figure 6 As shown, the preset number of times is twice, and the preset deflection angle is 15 degrees. Figure 6 In the illustrated embodiment, when the target moving object reaches the second point on the reference circle 300, after recording the movement trajectory of the target moving object between the first point 310 and the second point as the second welding path 400, a first deflection welding operation needs to be performed. At this time, the target moving object is controlled to rotate and deflect 15 degrees from the first point 310 with the preset welding point 100 as the center, and moves with the first point 310 of the deflected second welding path 400 as the starting point. When the target moving object reaches the second point of the deflected second welding path 400, the first deflection welding operation is confirmed to be completed. After that, a second deflection welding operation needs to be performed. Therefore, the target moving object is controlled to start from the first point 310 corresponding to the first deflection welding operation, deflect 15 degrees again with the preset welding point 100 as the center in the same rotation direction as the previous one, and moves with the first point 310 of the deflected second welding path 400 as the starting point. When the target moving object reaches the second point of the deflected second welding path 400, the second deflection welding operation is confirmed to be completed. In this embodiment, the initial undeflected second welding path 400 and the second welding path 400 deflected by 15 degrees twice can uniformly cover the reference circle, thereby fully and uniformly agitating the outer ring of the first welding path 200, thereby fully agitating and dispersing the ferrite in the molten pool, reducing segregation in the molten pool, avoiding the enrichment of ferrite in a certain area, improving metal fusion, and enhancing welding strength and welding stability.

[0072] like Figure 7As shown, in one embodiment, the second welding path 400 is located between the first boundary circle 710 and the second boundary circle 720; both the first boundary circle 710 and the second boundary circle 720 are centered at the preset welding point 100, the radius of the first boundary circle 710 is smaller than the radius of the second outer spiral of the first welding path 200; the radius of the second boundary circle 720 is larger than the radius of the first boundary circle 710, and the difference between the radius of the second boundary circle 720 and the radius of the first boundary circle 710 is less than or equal to the spiral spacing of the first welding path 200. Specifically, the spiral includes multiple spiral curves, the spiral curve at the outer edge of the spiral is the first outer spiral, and the spiral curve located inside the first outer spiral and close to the first outer spiral is the second outer spiral.

[0073] Understandably, since the Y-axis amplitude is smaller than the helical spacing of the first welding path 200, the transverse wave amplitude is smaller than the helical spacing of the first welding path 200, and the second welding path 400 is located between the first boundary circle 710 and the second boundary circle 720, the distance between the first boundary circle 710 and the reference circle 300 is smaller than the helical spacing of the first welding path 200; the distance between the second boundary circle 720 and the reference circle 300 is also smaller than the helical spacing of the first welding path 200. Setting these parameters ensures that the overlapping portion between the second welding path 400 and the first welding path 200 is within a controllable optimal range, which is beneficial for fully and uniformly agitating the outer ring portion of the first welding path 200.

[0074] like Figure 7 As shown, in one embodiment, the second welding path 400 includes a plurality of alternating tangentially connected first arcs 410 and a plurality of second arcs 420, wherein the first arcs 410 are internally tangentially connected to the first boundary circle 710, and the second arcs 420 are externally tangentially connected to the second boundary circle 720. It can be understood that in this embodiment, the second welding path 400 is an arc transverse wave vibration trajectory including a plurality of alternating tangentially connected first arcs 410 and a plurality of second arcs 420. When the laser beam moves alternately along the first arcs 410 and the second arcs 420, the heating area of ​​the laser beam is evenly and relatively dispersed, which can reduce the depth of the keyhole and molten pool penetrating the stacked component. This allows for a smoother transition of resolidified material between the preset welding point 100 of the stacked component and the surrounding area, thereby avoiding stress peaks, preventing burn-through of the stacked component, and improving the appearance of the weld joint.

[0075] In one embodiment, a preset offset distance is maintained between the target starting point 210 of the first welding path 200 and the preset welding point 100. Understandably, the first welding path 200 is a spiral line rotating around the preset welding point 100, starting from a preset offset distance away. The preset offset distance can be set as needed. Maintaining a preset offset distance between the starting point of the first welding path 200 and the preset welding point 100 helps avoid stress concentration at the keyhole.

[0076] An embodiment of the present invention also provides a laser welding apparatus, including a laser and a controller. The laser is used to emit a laser beam, and the controller is used to control the laser to perform the laser welding method. Understandably, the controller is used to control the laser beam to irradiate a preset welding point 100 on a stacked component to generate a keyhole and a molten pool surrounding the keyhole at the preset welding point 100; control a target moving object to move along a first welding path 200; after the target moving object has moved along the first welding path 200, control the target moving object to swing alternately in a first direction 320 and a second direction 330 radially along the reference circle 300, starting from a first point 310 on the reference circle 300; and when the target moving object reaches a second point on the reference circle 300, record the movement trajectory of the target moving object between the first point 310 and the second point as a second welding path 400.

[0077] Each module in the aforementioned controller can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor within the controller in hardware form or independent of it, or stored in the controller's memory in software form, so that the processor can call and execute the corresponding operations of each module.

[0078] In this embodiment of the invention, after a keyhole and a molten pool surrounding the keyhole are generated by laser beam irradiation at the preset welding point 100, the upper part of the molten pool is expanded by controlling the target moving object to move along the first welding path 200, thereby allowing the ferrite generated based on the high-temperature oxidation coating to be better dispersed along the fusion line. Then, the target moving object is controlled to move along the second welding path 400, thereby stirring the outer ring of the first welding path 200, further stirring and dispersing the ferrite structure in the molten pool, reducing segregation in the molten pool, avoiding the enrichment of ferrite in a certain area, improving metal fusion, and enhancing welding strength and welding stability.

[0079] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing related hardware with computer-readable instructions. These computer-readable instructions can be stored in a non-volatile readable storage medium or a volatile readable storage medium. When executed, these computer-readable instructions can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0080] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above.

[0081] The above are merely embodiments of the laser welding method and apparatus of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser welding method, characterized by, The method comprises: controlling a laser beam to irradiate a preset welding point on a stack to generate a keyhole and a molten pool surrounding the keyhole at the preset welding point; the stack comprises at least two metal workpieces stacked with each other; at least one of the metal workpieces is provided with a high-temperature oxidation-resistant plating layer; controlling a target moving object to move along a first welding path; the first welding path is a spiral line rotating around the preset welding point; the target moving object is at least one of the laser beam and the stack; after the target moving object moves along the first welding path, the target moving object is controlled to start from a first point on a reference circle, travel along the reference circle, and swing alternately in a first direction and a second direction in a radial direction of the reference circle; the first direction is a direction towards the center of the reference circle; the second direction is a direction away from the center of the reference circle; the center of the reference circle is the preset welding point; when the target moving object reaches a second point on the reference circle, a moving track of the target moving object between the first point and the second point is recorded as a second welding path; the second welding path at least partially overlaps with the first welding path; a preset number of deflection welding operations are performed, the deflection welding operation comprising: controlling the target moving object to move from a first point of the deflected second welding path, and confirming that the current deflection welding operation is completed when the target moving object reaches a second point of the deflected second welding path; wherein each of the second welding paths is deflected with the preset welding point as the center, and each of the second welding paths is deflected by a preset deflection angle relative to the second welding path formed in the previous operation.

2. The laser welding method according to claim 1, characterized in that, In the second welding path, a track of swinging alternately in the first direction and the second direction in the radial direction of the reference circle once is a circular swing track, and adjacent two circular swing tracks intersect.

3. The laser welding method according to claim 2, characterized in that, A first motion coordinate of the target moving object when moving along the second welding path is determined according to the following curve equation: S1(t)=[x1(t),y1(t)] x1(t) = v1 · t + a x1 • sin((2πf · t) - π / 2) y1(t) = a y1 • sin(2πf · t) wherein: t is a time point corresponding to the target moving object when moving along the second welding path; S1(t) is the first motion coordinate corresponding to the time point t in a first dynamic coordinate system; the first X direction of the first dynamic coordinate system is the tangent direction of the reference circle, and the first Y direction is the direction perpendicular to the first X direction in the plane of the reference circle; x1(t) is the first X coordinate in the first motion coordinate corresponding to the time point t; y1(t) is the first Y coordinate in the first motion coordinate corresponding to the time point t; v1 is a first preset motion speed of the center point of the circular swing track when traveling along the reference circle; a x1 is the X-directional amplitude, which is equal to one-half of the width of the annular swing trajectory in the first X-direction; a y1 is the Y-direction amplitude, which is equal to one-half the height of the annular swing trajectory in the first Y-direction.

4. The laser welding method according to claim 3, characterized in that, the Y-direction amplitude is smaller than the spiral line spacing of the first welding path, and the sum of twice the Y-direction amplitude and the spot diameter of the laser beam is greater than the spiral line spacing.

5. The laser welding method according to claim 3, characterized in that, The X-direction amplitude is determined according to the power of the laser beam and the first preset motion speed.

6. The laser welding method according to claim 1, characterized by, In the second welding path, a trajectory of the radial swing once along the first direction and the second direction alternately of the reference circle is a transverse wave vibration trajectory with one wavelength, and a connecting point between two adjacent transverse wave vibration trajectories is a wave crest or a wave trough.

7. The laser welding method according to claim 6, characterized in that, A second motion coordinate of the target moving object when moving along the second welding path is determined according to the following curve equation: S2(t) = [x2(t), y2(t)] x2(t) = v2t y2(t) = a y2 • sin(2tπf·t) Wherein: t is a corresponding time point when the target moving object moves along the second welding path; S2(t) is the second motion coordinate corresponding to the time point t in the second dynamic coordinate system; the second X direction of the second dynamic coordinate system is the tangent direction of the reference circle, and the second Y direction is the direction perpendicular to the second X direction in the plane where the reference circle is located; x2(t) is the second X coordinate in the motion coordinate corresponding to the time point t; y2(t) is the second Y coordinate in the motion coordinate corresponding to the time point t; v2 is a second preset motion speed of the center point of the transverse wave vibration trajectory along the reference circle; a y2 is the transverse wave amplitude of the transverse wave vibration trajectory in the second Y direction.

8. The laser welding method according to claim 7, characterized in that, The transverse wave amplitude is smaller than the spiral line spacing of the first welding path, and the sum of the transverse wave amplitude and the spot diameter of the laser beam is greater than the spiral line spacing.

9. The laser welding method according to any one of claims 1 to 8, characterized in that, The second welding path is located between a first boundary circle and a second boundary circle; the first boundary circle and the second boundary circle both have the preset welding point as the center, and the radius of the first boundary circle is smaller than the radius of the second outer spiral line of the first welding path. The radius of the second boundary circle is greater than the radius of the first boundary circle, and the difference between the radius of the second boundary circle and the radius of the first boundary circle is smaller than or equal to the spiral line spacing of the first welding path.

10. The laser welding method according to claim 9, characterized in that, The second welding path includes a plurality of first circular arcs and a plurality of second circular arcs connected alternately and tangentially, the first circular arcs are connected with the first boundary circle internally, and the second circular arcs are connected with the second boundary circle externally.

11. The laser welding method of claim 1, wherein, A target starting point of the first welding path is separated from the preset welding point by a preset offset distance.

12. The laser welding method of claim 1, wherein, The radius of the reference circle is smaller than or equal to the maximum distance between the first welding path and the preset welding point.

13. A laser welding apparatus characterized by comprising: A laser device and a controller are included, the laser device is used to emit a laser beam, and the controller is used to control the laser device to perform the laser welding method according to any one of claims 1 to 12.

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